U.S. patent number 5,482,862 [Application Number 08/337,125] was granted by the patent office on 1996-01-09 for methods for the on-line analysis of fluid streams.
This patent grant is currently assigned to The Dow Chemical Company. Invention is credited to Mark A. LaPack, Terry J. Nestrick, James C. Tou.
United States Patent |
5,482,862 |
LaPack , et al. |
January 9, 1996 |
Methods for the on-line analysis of fluid streams
Abstract
Method for optimizing a treatment for removing organic
substances from a chemical process stream wherein known quantities
and kinds of organic or other compounds are injected into and
dissolved in the stream prior to treatment thereof. Samples of the
compounds are extracted from the stream before and after treatment
thereof and compared with one another to determine the efficiency
of the treatment.
Inventors: |
LaPack; Mark A. (Midland,
MI), Nestrick; Terry J. (Midland, MI), Tou; James C.
(Midland, MI) |
Assignee: |
The Dow Chemical Company
(Midland, MI)
|
Family
ID: |
24731218 |
Appl.
No.: |
08/337,125 |
Filed: |
November 10, 1994 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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680462 |
Apr 4, 1991 |
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Current U.S.
Class: |
436/52; 422/68.1;
422/81; 436/55 |
Current CPC
Class: |
C02F
1/008 (20130101); G01N 33/1826 (20130101); G01N
35/1097 (20130101); G01N 2035/00465 (20130101); Y10T
436/119163 (20150115); Y10T 436/117497 (20150115); Y10T
436/255 (20150115); Y10T 436/12 (20150115) |
Current International
Class: |
C02F
1/00 (20060101); G01N 33/18 (20060101); G01N
1/00 (20060101); G01N 35/00 (20060101); G01N
035/08 () |
Field of
Search: |
;422/68.1,81
;436/52,54,55,178 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Housel; James C.
Assistant Examiner: Wallenhorst; Maureen M.
Parent Case Text
This is a continuation of applications Ser. No. 680,462 filed on
Apr. 4, 1991, now abandoned.
Claims
We claim:
1. A method of analyzing on-line a stream of liquid flowing to,
through, and beyond a treatment zone in which said liquid is
subjected to treatment to remove therefrom at least a portion of a
compound of interest that is at least partially immiscible with
said liquid, said method comprising dispensing a quantity of said
compound of interest into said stream so as to uniformly disperse
said compound of interest into said stream at a point upstream from
said zone; extracting from said stream downstream from said point
and upstream from said zone a first sample of said compound of
interest; treating said stream and the remainder of said compound
of interest in said zone; discharging said stream and any remaining
portion of said compound of interest from said zone; extracting
from said stream downstream from said zone a second sample of said
compound of interest; and analyzing the extracted first and second
samples to determine the effect of the treatment in said zone on
said compound of interest.
2. The method according to claim 1 wherein said compound of
interest is at least partially dissolved in said liquid.
3. The method according to claim 1 wherein said compound of
interest is dispensed into said liquid at such a velocity as to at
least partially dissolve said compound of interest in said
liquid.
4. The method according to claim 1 wherein said compound of
interest is mixed prior to the dispensing thereof into said stream
with a substance that is miscible with said compound of interest
and said liquid.
5. The method according to claim 1 wherein said extracted first and
second samples are analyzed independently of one another.
6. The method according to claim 1 wherein said compound of
interest is a liquid.
7. A method of analyzing on-line a stream of liquid flowing to,
through, and beyond a treatment zone in which said liquid is
subjected to treatment to affect at least one compound of interest
therein that is at least partially immiscible with said liquid,
said method comprising dispensing a quantity of said at least one
compound of interest into said stream; forming at a point upstream
from said zone a dispersion of said at least one compound of
interest in said stream; extracting from said stream downstream
from said point and upstream from said zone a first sample of said
at least one compound of interest; treating said stream and the
remainder of said at least one compound of interest in said zone
with a reagent capable of affecting said at least one compound of
interest; extracting from said stream downstream from said zone a
second sample of said at least one compound of interest; and
analyzing the extracted first and second samples to determine the
effect of the treatment in said zone on said at least one compound
of interest therein.
8. The method according to claim 7 wherein the quantity of said at
least one compound of interest dispensed into said stream is
known.
9. The method according to claim 7 wherein the dispersion of said
at least one compound of interest in said stream is substantially
uniform.
10. The method according to claim 7 wherein said at least one
compound of interest is dispensed into said stream
continuously.
11. The method according to claim 7 wherein said at least one
compound of interest is dispensed into said stream
incrementally.
12. The method according to claim 7 wherein said extracted first
and second samples are analyzed independently of one another.
13. The method according to claim 7 wherein the rate of flow of
said stream through said zone is varied.
14. The method according to claim 7 wherein said at least one
compound of interest is dispensed into said stream at a velocity
sufficient to effect a substantially uniform dispersion of said at
least one compound of interest in said stream.
15. The method according to claim 7 wherein said at least one
compound of interest is a liquid.
16. The method according to claim 7 wherein said at least one
compound of interest is mixed prior to the dispensing thereof into
said stream with a substance that is miscible with said at least
one compound of interest and said liquid.
17. The method according to claim 7 wherein said liquid is
water.
18. The method according to claim 7 wherein each of said extracted
first and second samples consists essentially of said at least one
compound of interest.
Description
This invention relates to methods for analyzing on-line fluid
streams and more particularly to apparatus and methods for
dissolving organic or other at least partially immiscible compounds
in aqueous streams to facilitate the evaluation of the efficiency
of processes for extracting such compounds from chemical process
streams.
BACKGROUND OF THE INVENTION
In analytical and process technology, it often is desirable to
generate a fluid mixture that is composed of components that
normally are at least partially immiscible with one another. In the
case of most analytical techniques, quantitation of a substance in
a sample matrix is determined by analyzing the sample and comparing
the resultant analytical response with the response obtained from
the analysis of prepared standard solutions of the analyte in the
same or similar matrix. For example, the quantitative analysis of
organic compounds in a wastewater sample is facilitated by
analyzing prepared standard solutions of organic compounds in
water.
Another application for a solution or mixture of typically
immiscible compounds is in a treatment for the destruction of
organic chemicals by biodegradation. Typically, the biodegrading
mass is supported in and sustained by a water matrix in which many
organic compounds may not readily dissolve. Effective treatment of
these compounds is highly dependent upon effective mixing of the
compounds in the water matrix.
The methods according to the invention provide dynamic mixing of at
least partially immiscible liquid streams and may be utilized in
the processes disclosed in applications Ser. Nos. 07/680,463 and
07/680,663, now abandoned.
SUMMARY OF THE INVENTION
Methods according to the invention enable organic or other at least
partially immiscible compounds to be mixed in liquid streams that
are to be analyzed or treated in a process.
Methods according to the invention may be performed by apparatus
wherein the process stream to be analyzed has all or a portion of
the influent pumped through a conduit to a treatment zone via a
membrane separator or other suitable means for extracting from the
influent a sample of a selected analyte of interest. Following
treatment of the stream in the treatment zone, the effluent passes
through a membrane separator or other suitable means which extracts
some or all of the selected analyte remaining in the stream
following the treatment. By analyzing the concentrations of the
analytes extracted from the influent and effluent streams it is
possible to determine the efficiency of the treatment process.
Methods according to the invention enable one or more of the
organic or other compounds typically contained in a process stream
and at least partially immiscible with the liquid constituting the
stream to be mixed and treated on-line for subsequent disposal. To
determine the most effective treatment to be performed on a process
stream containing a specific compound, a known quantity of such
compound is injected into a stream to the treated, following which
the mixture is treated and the treated effluent analyzed to
determine how effective the treatment was in removing the
compound.
The mixing is accomplished by injecting a known quantity of one or
more known at least partially immiscible compounds into a liquid
stream at such velocity as to ensure dissolution of the compounds
in the liquid stream, followed by stirring of the solution and
treatment thereof in a treatment zone in such manner as to remove
the compounds. The influent stream containing the dissolved
compounds may be sampled prior to treatment and the treated
effluent stream may be sampled to determine the effectiveness of
the treatment to which the influent stream was rejected. Sampling
of the influent and effluent streams may be effected by apparatus
and methods disclosed in the aforementioned applications.
THE DRAWINGS
Methods and apparatus for performing such method according to the
invention are illustrated in the accompanying drawings,
wherein:
FIG. 1 is a diagrammatic view of a presently preferred embodiment
of the invention;
FIG. 2 is a diagrammatic view of the injecting or spiking apparatus
and associated parts; and
FIG. 3 is a greatly enlarged, partly sectional view of a portion of
the spiking apparatus.
THE DISCLOSED EMBODIMENT
The invention is especially adapted for use in conjunction with the
apparatus shown in FIG. 1 which enables organic or other compounds
contained in continuously flowing streams of gases or liquids, or
both, to be identified and characterized. The apparatus corresponds
to that disclosed in the aforementioned patent applications, to
which reference may be had for a more detailed disclosure. Briefly,
however, the apparatus comprises a process or treatment zone 1
formed by suitable means such as a retort or reactor 2, into,
through, and beyond which a process stream flows. The stream flows
toward the reactor through an influent inlet 3 in communication
with a gas or liquid source 4 via a variable speed pump 5 and in
communication with the reactor 2 via an adjustable, flow control
valve 6 and a membrane separator 7.
The process stream may flow into, through, and out of the treatment
zone 1 at variable, controlled flow rates as determined by the pump
5, the valve 6, or both. The reactor 2 may be any one of a number
of suitable kinds and is capable of containing a solid reagent,
such as activated charcoal, an active or inactive biodegrading mass
(biomass), or a liquid or a gas in addition to or to the exclusion
of the other reagents referred to above. The contents of the
reactor will depend upon the specific process streams to which the
apparatus is applied, and such process streams include waste water;
fermentation reactions; stripping, distillation, and absorption
columns; and degasing units, for example.
An effluent outlet 8 communicates with the reactor 2 via an
adjustable valve 9 and a membrane separator 10 similar to the
separator 7. The outlet 8 communicates also with a drain, vent, the
source 4, or other destination as may be appropriate.
The apparatus includes a rotary selector switch 12 having a
plurality of inlet ports 13 and 14 connected by tubes 15 and 16 to
the membrane separators 7 and 10, respectively. The selector switch
has an exhaust port 17 connected via a line 18, an exhaust pump 19,
and a tube 20 to a collector, vent, or other suitable device.
The switch 12 has a rotor 21 which carries a coupling tube 22 that
may be connected to any selected one of the ports in response to
rotation of the rotor. The switch also includes a stationary
delivery tube 23 in communication with an analyzer 24. The analyzer
is one that is appropriate for analysis of the kinds of analytes
extracted from the fluid streams by the separators.
Operatively coupled to the analyzer 24 in known manner is a
controller 25. The controller may be a computer such as that
designated PDP 11-73 by Digital Equipment Corporation. The
controller is connected to a power source (not shown) and to the
valves 6 and 9 by control lines 26 and 27, respectively, for
adjusting the valves to vary the rates of flow of fluid
therethrough.
The membrane of the separator 7 is permeable to a selected compound
of interest contained in the influent fluid and the membrane in the
separator 8 is permeable to the same or different compound,
depending on the treatment occurring in the zone 1, whether the
process is one which extracts or adds compounds, and the analysis
to be made.
In the use of the apparatus thus far described, influent process
liquid is delivered to the treatment zone 1 via the pump 5, the
inlet 3, the valve 6, and the membrane separator 7. The rate of
flow of the influent liquid is controlled by the pump, the valve,
or both. The separator 7 extracts a sample of the selected compound
from the influent whence it is delivered to the port 13 of the
switch 12 via the tube 15. Movement of the rotor 21 of the switch
12 will establish communication between the port 13 and the
analyzer 24 to enable the extract to be identified and
characterized.
The liquid delivered to the treatment zone 1 is acted upon by
whatever reagent or reagents are accommodated in the reactor 2. The
specific reagent utilized will be selected for its ability to react
in a known manner with the particular influent fluid and organic or
other compounds therein.
Liquid which traverses the reactor 2 will react with the reagent(s)
and be discharged through the effluent outlet 8 via the valve 9 and
pass through the separator 10 to a collector, drain, or other
destination. If the membrane of the separator 10 is permeable to
the same compound extracted by the separator 7, it will extract a
sample containing some or all of the same compound remaining (if
any) in the effluent fluid and deliver it via the tube 16 to the
port 14. Adjustment of the rotor 21 to connect the tube 22 to the
port 14 will enable the extracted sample to be delivered to the
analyzer 24 for analysis.
Whenever the separators 7 and 10 are not being used for analysis
purposes, they, their respective tubes 15 and 16, and the ports 13
and 14 are purged by the pump 19, the line 18, and the port 17, it
being understood that internal passages are provided in the switch
12 for this purpose, as is conventional.
By comparing the analyses of the influent and effluent fluids, the
presence and concentration of the compound of interest in the
effluent may be detected and compared with the concentration of
such compound in the influent fluid, thereby enabling the
effectiveness of the treatment performed in the treatment zone 1 to
be evaluated. If it is determined that more or less residence time
of the influent fluid in the reactor is required, the valves 6 and
9 may be adjusted appropriately, either manually or automatically
by the controller 25 via the connections 26 and 27,
respectively.
It also is possible from the comparison of the analyses of the
influent and effluent fluid samples to ascertain the effectiveness
of the reagent or reagents accommodated in the reactor, thereby
enabling appropriate decisions to be made concerning modification
or replacement of such reagents.
It will be apparent from the foregoing that the apparatus disclosed
thus far is capable of substantially simultaneous on-line analysis
of influent and effluent streams, any delay between successive
analyses being that necessitated by adjustment of the rotor 21 of
the selector switch 12. It also will be apparent that the treatment
to which the influent fluid is subjected in the treatment zone may
be controlled or varied by adjustment of the rates of flow of such
streams. During a given analysis period, however, the rates of flow
of the streams should be maintained constant.
The apparatus and methods disclosed herein are intended primarily
to evaluate the effectiveness of the treatment performed in the
treatment zone 1 with respect to specific organic or other
compounds, thereby making it possible to adjust the rate of flow of
the streams and/or incorporate in the reactor reagents especially
adapted for use with such compounds. This objective may be achieved
by injecting into the influent stream a known quantity of a known
organic or other compound, dissolving the compound in the stream,
and analyzing both the influent and effluent streams as described.
Injection of the known compound may be achieved by spiking
apparatus 30 that is best shown in FIGS. 2 and 3.
The spiking apparatus 30 includes a source 31 of a selected
compound. For illustrative purposes the source is shown as
constituting a syringe pump corresponding to that manufactured by
Sage Instruments and having a barrel 32 within which is a plunger
33 driven incrementally or continuously at a selected speed by a
variable speed motor 34, depending on whether the treatment is a
batch or a continuous process. The plunger has adjacent its inner
end a groove in which is accommodated a sealing O-ring 35. At the
discharge end of the barrel is a fitting 36 to which is connected
one end of a tube 37, the opposite end of which is accommodated in
a fitting 38 from which a hollow needle 39 extends. Suitable seals
40 encircle one end of the needle 39 whereas the opposite end
thereof extends into a cavity 41 formed in one branch 42 of a Tee
fitting 43 which communicates with the interior of the influent
conduit 3 between the valve 6 and the separator 7. The cavity 41 is
closed by a seal 44.
Accommodated within the needle 39 is a capillary tube 45 having a
bore of greatly reduced diameter compared to the diameters of the
bores of the needle and the tube 37. For example, the bore of the
tube 45 may be such as to provide a calculated 400-fold increase in
linear velocity of the fluid substance dispensed from the syringe
barrel 32. This construction is one that is especially adapted for
injecting organic or other substances into the conduit 3 that are
substantially immiscible with the influent fluid. The velocity at
which such substances are injected into the contents of the
influent conduit 3 results in adequate dissolution of the spiking
substance in the influent liquid.
An appropriate material for the tube 45 is fused silica or any
other material that is inert to the injected compound. The free end
of the tube 45 constitutes a nozzle for injecting the selected
substance directly into the influent liquid in the cavity 41. In
some instances it may be desirable to disperse the spiking compound
in a substance, such as acetone, that is miscible in both the
spiking compound and the influent to facilitate dissolution of such
compound in the process stream.
It is preferred to interpose a mixing vessel 46 between the spiking
apparatus 30 and the membrane separator 7 to ensure thorough mixing
of the influent and to provide a trap for any particulate material
which may be entrained in the stream. Such a vessel includes a cap
47 through which inlet and outlet tubes 48 and 49, respectively,
pass in sealed relation. Within the vessel is a magnetic stirrer 50
or other suitable agitator.
In the use of the apparatus a known quantity of the known spiking
compound is injected into and dissolved in the process stream
influent and delivered to the treatment zone 1 via the inlet 3 and
the separator 7. The solution delivered to the treatment zone 1 is
subjected to treatment by the reagents in the reactor 2, following
which the treated influent is discharged from the reactor via the
conduit 8, the valve 9, and the separator 10. The compounds
separated in the separators 7 and 10 are delivered to the switching
valve 12 for analysis independently of one another by the analyzer
24.
The rotary switching valve 12 and the analyzer 24 make it possible
to compare on-line at any selected time the concentration of a
selected compound in the spiked influent and the concentration of
such compound in the treated effluent. The effectiveness of the
treatment of the influent fluid performed in the treatment zone 1
may be ascertained by comparing the results of the analyses of the
influent and effluent streams.
The injection of the spiking fluid is accomplished by movement of
the plunger 33 of the pump 31 in a direction to dispense the
contents of the barrel 32. This may be accomplished manually, but
it is preferred to activate the spiking apparatus automatically in
accordance with a predetermined program. Thus, the controller 25
may be coupled by a power line 51 to the motor 34 forming part of
the syringe pump to advance the plunger continuously or at
predetermined intervals and inject a known quantity of a selected
compound into the influent fluid. Alternatively, any controllable
speed pump may be used to deliver the spiking compound to the
stream. The selected compound is one that is extractable in the
separators 7 and 10.
The ability to inject and dissolve a known quantity of a known
organic or other compound in a chemical process stream upstream
from a treatment zone makes it possible to determine not only what
kind of treatment should be performed on such stream to remove such
compound, but also the efficiency of such treatment.
* * * * *